Smoking dependency is a complex social problem with significant public health impact. Various methods of smoking cessation are being promoted, but with generally disappointing rates of success. Conversely, 95% of those who do successfully stop smoking do it on their own without participation in a formal program. The aim of this two-year study is to identify the psycho-social and environmental factors which are related to both successful and unsuccessful non-formalized attempts at smoking cessation. Samples from five populations will be selected according to the participants' previous smoking history. Three of these populations are past, present and future clients in service programs operated by the School of Public Health - Health Testing Team, Heartbeat and Center for Dependent Behavior. The other two populations are outpatients at a veterans hospital, and a general population selected by a Random Digit Telephone Survey. Individuals with a smoking history will be selected from each population and categorized into one of four groups: 1) Current nonsmokers who have not smoked for 6 or more months, 2) current smokers who stopped smoking for 1 week or longer, 3) those who attempted to stop but had an abstinence period of less than one week, and 4) those who never attempted to stop smoking. Each participant will fill out a questionnaire providing selected demographic, psycho-social, environmental and other characteristics. For three of the study groups - Health Testing Team, Heartbeat and Center for Dependent Behavior -this data will be analyzed together with previously obtained information. Using these data we will be able to determine differences in characteristics of smokers who were successful or unsuccessful in smoking cessation and determine the role that a variety of factors play in successful smoking cessation. This new information on a variety of factors influential in self-help smoking cessation attempts should be useful in developing more effective cessation techniques for specific population groups.